|Yuan, Yongping - UNIV. OF MISSISSIPPI|
Submitted to: American Water Resources Association Summer Specialty Conference
Publication Type: Proceedings
Publication Acceptance Date: April 30, 2004
Publication Date: June 28, 2004
Citation: Yuan, Y., Bingner, R.L., Williams, R.G., Lowrance, R.R., Bosch, D.D., Sheridan, J.M. 2004. Integration of annagnps and remm for watershed riparian buffer system assessment. In: Proceedings American Water Resources Association Summer Specialty Conference "Riparian Ecosystems and Buffers: Multi-Scale Structure, Function, and Management", June 28-30, 2004, Olympic Valley, California. CDROM. Interpretive Summary: The development of management practices used to reduce pollutants produced from agricultural fields entering stream systems is critical in improving overall watershed water quality. The implementation of riparian buffer areas along streams can be a management approach utilized throughout a watershed with a minimal impact on farming practices. The evaluation of the effectiveness of the buffers using conventional measurement techniques can be difficult because of the nature of water slowly flowing through the vegetation that comprises the buffer. In order to better assess riparian buffers, computer simulation models have been developed to separately evaluate riparian buffer areas and the upland contributions to the riparian areas. This study combines the simulation approach of an upland computer model and a riparian buffer system model to assess the capability of the combined models to perform these watershed evaluations. This study will also be used to determine the feasibility of developing a more comprehensive and integrated modeling approach needed to evaluate the impact of agricultural production practices along riparian buffer systems throughout a watershed system. Using a monitored watershed in Georgia, the simulation approach was able to demonstrate a five-year sediment reduction of 93% as a result of the riparian buffer. The majority of the soil in the study site was comprised of sand material, which the buffer effectively trapped completely, as well as some silt and to a lesser extent clay material. Attached with the trapped sediment were nitrogen and phosphorus components that the models also were able to accurately reflect. These technological tools are critical in evaluating the best management approach for any individual watershed. By using these tools on any watershed in the United States, watershed managers will be able to apply a systematic approach in determining the best practices available to improve watershed water quality.
Technical Abstract: The USDA Annualized Agricultural Non-Point Source Pollution model (AnnAGNPS) has been developed to aid in the evaluation of watershed response to agricultural management practices. Through a continuous simulation of surface and subsurface runoff, sediment and chemical non-point source pollutant loading from watersheds, best management practices (BMPs) can be evaluated. However, AnnAGNPS does not currently contain features to estimate the effect of riparian buffer systems (RBS) on water quality. Capabilities of AnnAGNPS to simulate the effect of RBS within watershed systems would enhance the application of the model for watershed assessments. The Riparian Ecosystem Management Model (REMM) has been developed by USDA-ARS to simulate the water quality impacts of riparian and other edge of field buffer systems. REMM is a tool to assess the function of RBS to filter pollutants from a field. However, information on upland water and pollutant loading from fields to the RBS for REMM is normally lacking and preparing this information can be very time consuming. This can be improved by using AnnAGNPS to provide upland loadings to REMM. The development and integration of AnnAGNPS and riparian buffer technology from REMM would provide a powerful tool that can evaluate the impact of agricultural management practices as well as RBS at a watershed scale. A first step in this integration process is to understand the needs of REMM and the capability of AnnAGNPS to provide information required to evaluate the RBS. In this study, AnnAGNPS was used to simulate water and pollutant loadings from upland field to riparian buffers at the Gibbs Farm in the Georgia coastal plain. These AnnAGNPS outputs were used as the inputs to REMM. AnnAGNPS simulated upland loadings were compared with observed upland loadings and output from riparian buffer zones simulated by REMM.